Apparatus for the production of music



B. F. MIESSNER ET AL APPARATUS FOR THE PRODUCTION OF MUSIC Filed Oct. 11, 1932 Oct. 3, 1933.

2 Sheets-Sheet l FMM IN V EN TOR5.'

Oct. 3,1933. 5, MIESSNER r AL 1,929,032

APPARATUS FOR THE PRODUCTION OF MUSIC Filed Oct. 11, 1932 2 Sheets-Sheet 2 9, INVENTORS:

Patented Oct. 3, 1933 OFFICE}- 1,929,032 I APPARATUS ron THE PRODUCTION OF MUSIC Benjamin F. Miessner, Millburn Township, Essex County, and Charles T. Jacobs, New Provideuce Township, Union County, N. 1., assignors to Miessner Inventions, Inc., a corporation of New Jersey Application October 11, 1932. Serial No. 837,256

' 18 Claim.

This invention relates to musical instruments of the .type wherein the output sound is translated from electric oscillations, and more particularly to such instruments in which the oscillations so translated are obtained by selectivecombination or algebraic addition of the oscillations of a plurality of separate series. A musical instrument of this type, in which the oscillations of the separate series are of similar fundamental frequency but of respectively different waveform, has en disclosed and claimed in the United State Patent Number 1,908,607 to Charles T. Jacobs, issued May 2, .1933. Therein it was shown that selective combination of the oscilla tions of the several different series makes possi-- ble the production of a wide range of output tone' qualities, or harmonic. structures. The instant invention is concerned with improvements in s the controls for effecting such selective combina- 20 tion, and with a musical instrument in which such improvements are incorporated.

Thus it is an object of our invention to provide improved controls for selectively effecting any of a number ofpredetermined oscillation combinations. It is a furtherobiect to provide improved controls for selectively eflecting such oscillation combinations and simultaneously effecting read- Justments of the relative strengths of the various partial components of the, combined oscillations. It is a still further object to provide a musical instrument of the class described'characterized by the fulfilment of. the objects abovesset forth. Other and allied objects will more fully appear from the following descriptionand the appended to the Figure 1 is a schematic diagram illustrating our invention in asimple form;

Figure 2 is a schematic diagram illustrating our invention in a modified and preferred form; and

Figure 3 is a schematic diagram illustrating a particular feature of our invention.

In the patent above referred to a single multithrow multi-pole switch was shown as a meansof effecting selectively any of a plurality of predetermined oscillation combinations. -We have found, however, thatthe rapid manipulation of such a switch during playing of aninstrument is claims: I

In such description reference is had accompanying drawings, of which dimcult; and according to the present invention a switch is provided foreach of the total number of predetermined oscillation combinations. Such an arrangement of switches may take any of a variety of forms, and may advantageously be employed with various refinements, as hereinafter more fully appears. I 1

In Figure 1 there is illustrated a very simple arrangementof the type described, suitable for the combination of oscillations of four diiferent series-i. e., oscillations from four different sources. Reference being had to the figure, there will be seen four oscillation generators 1, 1a, 1b and 10 whose outputs are to be selectively combined. It will be understood that no limitation to any particular form of generator is implied, it being intended only that the simultaneous outputs of all the generators be always suitable for combination to produce a single musical tone or any other musical effect. Each of the'generators is shunted by a resistance-i. e., 2, 2a, 2b and 2c respectivelyacross which it develops a voltage. The output leads 3a and 3b, across which the combined oscillations are to appear, are connected to the electrical centers 4 and 4c of resistances 2 and 20 respectively, while the centers 4a and 4b of resistances 2a and 2b are connected together. A plurality of double-pole, single-throw switches 5 are provided, one for each particular oscillation combination or tone quality desired. Each may comprise a pole 10 and a pole 11, operating in unison. The closing of pole 10 of each switch may connect a tap on resistance 2 to a tap on'reslstance 2a, while the closing of pole 11 of each switch may connect a tap on resistance 2b to a tap on resistance 20. 1

The center switch 5 is illustrated closed. Thus tap 8 on resistance 2 is connected to tap 8a on resistance 22;. and tap 81: on resistance 2b to tap 8c on resistance 2c. Between the output leads 3a and 3b there are therefore connected the sections 4-8 of resistance 2, 8a-4a of resistance 2a, 4b-8b of resistance 2b and 80-40, of -resistance 2c. The voltages appearing "across each of these sections are them-action of such tap from the center point. p

The proper positions for the tapssuch as 8, 8a, 8b and 8c to be'connected to each switch is, of course, afunction of the tone qualities desired and ,of the harmonic structures available in the generators 1, la, 1b and 1c; such tap positions are best determined by test under the particular conditions existing in a given case;

The operation of the system of Figural having been described,-it will be apparent that the function of the resistances 2, 2a, 2b and 2c is that of subdividing, in respect of amplitude, the oscillations derived from the generators 1, 1a, 1b and 1c.

It will be seen that with the switching method illustrated in Figure 1, the outputs of four generators may be selectively combined by the use of two-pole switches. It is obvious that the outputs of two generators might be selectively combined by single-pole switches, those of six generators by three-pole switches, etc.i. e., that each switch pole takes care of two generators.

In the system as thus far described it is intended that only one of the switches 5 be closed at, a time. Should the system be used with two or more switches simultaneously closed, the harmonic structure of the resulting oscillation combination (or output tone upon translation into sound) will not necessarily have any relation to the harmonic structure of the oscillation combinations effected by the system with the same switches when closed one at a time. It is possible, however, to arrange the system so that with two or more switches simultaneously closed the harmonic structure of the resulting oscillation combination will approximately correspond to that of the superposition of the oscillation combinations effected by the same switches separrately closed. This may readily be accomplished by inserting a resistance 17 in series with each pole 10 and 11 of each switch 5. The value of these resistances is preferably at least twice that of each of theresistances 2, 2a, 2b and 2c, and at the same time preferably low compared to the input impedance of the apparatus into which the output leads 3a and 3b feed. It is to be noted that while the harmonic structure of the oscillation combination withtwo or more switches closed will approximately correspond to the superposition of the oscillation combination effected by each switch separately, the overall amplitude of the oscillation combination will correspond rather to the average of the amplitudes obtained from each switch separately.

Of the two output leads 3a and 3b one may conveniently be grounded or connected to a low potential. Thus the lead 3a has been indicated in Figure 1 as grounded. We have found that the permanent connection of the ungrounded lead 3b to one of the resistance systems-4. e., to 20 in Figure 1-may result in the impression on this lead of oscillations from the generator connected to this resistance system-i. e., from generator lcwhen all the switches 5 are open. This appears to result from stray capacities of this generator to ground, which are usually difficult to eradicate in practice. In order to avoid this impression of oscillations with all switches open, we prefer to employ one of the poles of each switch fora single generator only, connecting this pole of each switch, or the'ccntact to which it closes, to the ungrounded or higher potential output lead 3b. This of course reduces by one the number of generators which may be taken care of by any given number of poles.

Such an arrangement has been illustrated in Figure 2. Herein a plurality of three pole switches 6 are employed; but it is convenient at this point of the disclosure to consider only the portion of Figure 2 lying to the left of the line AA, and the switches 6 may therefore be considered for the, present as two-pole switches similar to the switches 50f Figure 1 and similarly having poles 10 and 11. It will be that the output lead 3b is connected to the contact on each switch against which the pole 11 closes, and that no generator-resistance system corresponding to the system lc2c of Figure 1 appears in Figure 2. The other three generators of Figure 1 are illustrated in Figure-2, by way of example of a useful arrangement, as transformers 14, 14a and 14b having primaries respectively connected to the outputs of three mechanico-electric translating devices 13, 13a and 13b. The latter are positioned in spaced relation respectively to three points along a tuned string 15, excitable as by hammer 16. Each translating device may comprise for example a permanent bar magnet surrounded by a coil of fine wire, but it will be understood that any other form of mechanico-electric translating device may be employed. Each such device will be understood to deliver to its associated transformer a series of oscillations corresponding in waveform and other characteristics to the vibration of the string point to whichit is adjacent; and as the latter have respectively different vibrational waveforms, electric oscillations of respectively different waveform will appear across the secondaries of the three transformers 14, 14a and 14b, these therefore corresponding to the three generators 1, 1a and 1b of Figure 1.

It will be seen in Figure 1 that if all the switches 5 are open, the resistance-generator systems 20- la and 2b1b while mutually connected together,

are completely disconnected from the rest of the circuit. We have found that under these conditions these systems tend to acquire an electrostatic charge, and to discharge upon closing of any of the switches with an'attendant transient disturbance. We have found that this condition is readily corrected by connecting some point in each of these systems (conveniently the lead joining them) to ground (or to some portion of the circuit never completely disconnected from ground) through a resistance. Such a resistance is shown in Figure 2 as 56. Its value may be very high, and preferably is so in order to prevent any significant effect on the operation of the resistance systems 2, 2a and 2b.

. The. top-illustrated switch 6 in Figure 2 has been shown connected to movable contacts on the respective resistances 2, 2a and 2b instead of to fixed taps thereon. Thus there is provided means of effecting any special oscillation combination which may be desired but which is not included among the several combinations respectively effected by the other switches 6.

When employed, as shown in Figure 2, with translating devices variously arranged along or about the same vibrator or vibrators, a system of the type described effects control of the harmonic structure of the .output oscillations on the basis of particular partial components of the vibration of the vibrators. It has been shown in the co-pending application of Benjamin F. Miessner, Serial Number 566,628, filed October 3, 1931, that there may advantageously be employed in association with a system so selective as to particular partials, a system for the regulation of the relative strength of different frequency components of the output oscillations on an absolute frequency basis. Further, in the co-pending application of Charles T. Jacobs, Serial Number 666,,- 6'73, flied April 18, 1933, a useful circuit is disclosed 1 whereby the transmission-frequency characteristic of the electrical system in a musical instrument of the class described may be'varied to effect such regulation of component strengths on an absolute frequency basis. Such a circuit comprises an auto-transformer and a variable resistance in series with the primary end of the auto-transformer, the input of the circuit comprising the primary and variable resistance, and the output .the entire auto-transformer and variable resist- Accordingly we have shown such a circuit in Fig-- ure 2 (to the'right of the line AA) in the form of auto-transformer 18 and resistance 19, various portions of which latter may be shorted out, to adjust its effective value, by an extra pole 20 on eachoscillation combining switch 6.

Following the circuit for adjustment of transmission-frequency characteristic there is preferably a very high or infinite impedance; we consequently show this circuit feeding into the grid circuit of an amplifying .thermionic vacuumtube 50, whose cathode and anode current supplies are shown as 21 and 22 respectively. Bias for the grid of tube 50 may be developed by the anode current of this tube across condensively bypassed resistance 23. In the output circuit of this tube there may be provided for example in succession transformer 24, volume control or potentiometer 25, further ampliler 26 and loudspeaker or other electro-acoustic translating device 2'7.

We have frequently found it desirable to arrange a system such as that of. Figure 2 so that only one switch 6 is closed at a time. Accordingly we illustrate in Figure 3 automatic means for opening any switch closed at the moment of depression of any other switch. In Figure 3 will be seen a group of three of the switches 6 of Figure 2, but it will be understood that any desired number of such switches may be employed. To each switch 6,with its three poles 10, 11 and 20, is added a fourth pole 28 which connects to contact 29 when switch 6 is closed and to contact 30 when switch 8 is open. Contacts 29 and 30 may be electricaly connected together. A spring 31 may be attached to pole 28, or to one of the other poles, normally to hold the switch 6 open and the pole-28 in contact with 30. An armature 34 of magnetic material may be provided on pole 28, attractable by electromagnet 32 upon energization of the latter. A circuit may be formed by connecting in series the switches formed by poles 28 and contacts 29 and 30, and

the electr'omagnets, 32, the circuit being completed by battery or ,other magnetizing current source 33.

Each electromagnet 32 is made too weak to attract its armature 34 against the force of spring 31 when pole 28 is in contact with 30 (and switch 6 open). The strength of the electromagnet 32 is sumcient, however, to hold armature 34 in contact with its extremity if pole 28 is moved into contact with 29 (and switch 6 closed). as may be done for example by pressing on button 35. It will be seen, however, that in the operation of closing any switch 6 the pole 28 associated therewith is momentarily out of contact witheither 29 or 30. During this time interval all the electromagnets 32 are de-energized, and any other switch 6 which may be closed at the moment 'will be opened by its spring 31. Only by the simultaneous closing of two or more switches 6, or by manually holding closed one or more 3 switches while another or others are closed, may there be defeated the action of limiting to one the number of switches closed at a time. If desired an additional normally closed switch 36 may be provided in series with battery or source 33, by momentary opening of which switch there may be opened all switches-=6 closed at the time.

While we have described the various elements of our invention in terms of specific embodiments thereof, we do not intend to imply limitations to such embodiments, but rather intend to express the scope of our invention by the appended claims.

. We claim:-

1. In a musical instrument, the combination of a plurality of generators of electric oscillations of similar fundamental frequency but of respectively different waveform; and a plurality of selectively operable switches each, connected to each of said generators and arranged to effect a 'harmonically different predetermined combination of the oscillations therefrom.

2. In a musical instrument, the combination of a plurality of generators of electric oscillations of similar fundamental frequency but of respectively different waveform; a plurality of means respectively connected. to said generators for subdividing the oscillations therefrom in respect of amplitude; and a plurality of selectively operable switches, each connected to each of said subdividing means and arranged to effect a harmonically different predetermined combination of said subdivided oscillations.

3. In a musical instrument, the combination of a plurality of generators of electric oscillations of similar fundamental frequency but of respectively different waveform; a plurality of means respectively connected to said generators for subdividing the oscillations therefrom in respect of amplitude; a plurality of selectively operable switches, each connected to each of said subdividing means and arranged to effect a harmonically different predetermined combination of said subdivided oscillations; and means connected to said switches for rendering substantially cumulative, upon simultaneous operation of a plurality of said switches, the harmonic structures of the oscillation combinations effected by separate operation of each such switch.

4. In a musical instrument, the combination of a plurality of generators of electric oscillations of similar fundamental frequency but of respectively diflercnt waveform; a plurality of selectively operable switches, each connected to each of said sources and arranged when closed to effect a harmonically different predetermined combination of the oscillations therefrom; and means for opening all other said switches closed upon the closing of any one of said switches.

15. In a musical instrument, the combination of a plurality of generators of electric oscillations of similar fundamental frequency but of respectively diiferent waveform; a plurality of selectively operable switches, each connected to each of said sources and arranged when closed to effect a harmonically din'erent predetermined combination of the oscillations therefrom: and means connected to said switches for efl'ecting, upon the closing of any said switch, a respective predetermined alteration of the relative amplitudes of different frequency components of said combined ouillations on an absolute frequency of a tuned vibrator; a plurality of mechanicoelectric translating devices, each arranged to translate the vibration of a different portion of said vibrator into electric oscillations; and a plurality of selectively operable switches, each connected to each of said translating devices and arranged to effect a harmonically different predetermined combination of the oscillations therefrom.

7. In a musical instrument, the combination of a tuned vibrator; a plurality of mechanicoelectric translating devices, each arranged to translate the vibrationof a different portion of said vibrator'into electric oscillations; a plurality of means respectively connected to said translating devices for subdividing the oscillations therefrom in respect of amplitude; and a plurality of selectively operable switches, each connected to each of said subdividing means and arranged to effect a harmonically different predetermined combination of said subdivided oscillations.

8. In a musical instrument, the combination of a tuned vibrator; a plurality of mechanicoelectric translating device's, each arranged to translate the vibration of a different portion of said vibrator into electric oscillations; a plurality of means respectively connected to said translating devices for subdividing the oscillations therefrom in respect of amplitude; a plurality of selectively operable switches, each connected to each of said subdividing means and arranged to effect a harmonically different predetermined combination of said subdivided oscillations; and means connected to said switches for rendering substantially cumulative, upon simultaneous operation of a plurality of said switches, the harmonic structures of the oscillation combinations effected by separate operation of each such switch.

9. In a musical instrument, the combination of a tuned vibrator; a plurality of mechanicoelectric translating devices, each arranged to translate the vibration of a different portion of said vibrator into electric oscillations; a plurality of selectively operable switches, each connected to each of said translating-devices and arranged when closed to effect a' harmonically different predetermined combination of the oscillations therefrom; and means for opening all other said switches closed upon the closing of any one of said switches.

10. In a musical instrument, the'combination,

of a tuned vibrator; a plurality of mechanicaelectric translating devices, each arranged to translate, the vibration of a different portion of said vibrator into electric oscillations; a plurality of selectively operable switches, each connected to each. of said translating devices and arranged when closed to effect a harmonically different predetermined combination of the oscillations therefrom, and means connected to said switches for effecting,\uponthe closing of any 'said switch, a respective predetermined alteration of the relative amplitudes of different frequency components of said combined oscillations on an absolute frequency basis.

11. In a musical instrument, the combination of a plurality of impedances; means for applying across said impedances electric oscillations to be selectively combined; 'a work circuit adapted to receive tap on a fourth of said impedances to said work circuit; a connection between fixed taps on a second and a third of said impedances; and a plurality of selective means each operable to consaid combined oscillations; con-' nections from a fixed tap on a first and a fixed to said work circuit; a connection between fixed taps on a second and a third of said impedances;

and a plurality of selective means each operable to connect a point on said first to a point on said second impedance and a point on said third impedance to said work circuit.

13. In a musical instrument, the combination of a plurality of impedances; means for applying across said impedances electric oscillations to be selectively combined; a work circuit adapted to receive said combined oscillations; connections from a fixed tap on a first and a fixed tap on a fourth of said impedances to said work circuit; a connection between fixed taps on a second and a third of said impedances; and a plurality of selective means each operable to effect a connection of a point on said firstito a point on said second impedance and a connection of a point on said third to a point on said fourth impedance and resistances respectively inserted in said last mentioned connections.

14. In a musical instrument, the combination of a plurality of impedances; means for applying selectively combined; a work circuit adapted to receive said combined oscillations; a connection from a fixed tap on a first of said impedances to said work circuit; a connection between fixed taps on a second and a third of said impedances; and a plurality of selective means each operable to effect a connection of a point on said first to a point on said second impedance and a connection of a point on said third impedance to said work circuit and resistances respectively inserted in said last mentioned connections. f

15. In a musical instrument, the combination of a plurality of impedances; means for'applying across said impedances electric oscillations to be selectively combined; a work circuit adapted to receive said combined oscillations; connections from a fixed tap on a first and a fixed tap on a fourth of said impedances to said work circuit; a connection between fixed taps on a second and a third of said impedances; a plurality of selective means each operable to connect a point on said first to a point on said second-impedance, and a point on said third to a point-on said fourth impedance; andmeans operable to adjust the transmission-frequency characteristic of said work circuit, said last mentioned means being connected to said selectiv'e'means for simultanneous operation therewith.

16. In a musical instrument, the combination oi a plurality of impedances; means for applying across said impedances electric oscillations to-be selectively combined; a work circuit adapted to receive said combined oscillations; a connection from a fixed tap on a first of said impedances to said work circuit; a connection between fixed taps on a second and a third of said impedances; a plurality of selective means each operable to connect a point on said first to a point on said second impedance, and a point on said third impedance to said work circuit; and means operable to adjust the transmission-frequency characteristic of said work circuit. said last mentioned basis of particular or Similar fundamental frequency but 01 respec tively diirerent waveform; a plurality 0! n w! respectively connected to said generators for sub dividing the oscillations thereirom in respect of fixed taps and a variable contact on each of said subdividing means? and selective harmonicallydifl'erent comsubdivided oscillations, said means including a plurality of selectively cper-= able switches each connected to one 01' said ilxecl tape on each subdividing means, and an additional selectively operable switch connected to said adiustable contacts.

- BENJAMIN F. MESSNER.

CHARLES T. JACOBS. a

means for effecting loinaticns or? said 

